docs: def _get_filter_modifier(self, field):
          """Detect the filter modifier"""
          tokens = field.split(FIELD_SEPARATOR)
          if len(tokens) == 1:
              return field, ""
          if tokens[-1] in self.FILTER_OPERATORS.keys():
              return u'.'.join(tokens[:-1]), tokens[-1]
          return u'.'.join(tokens), ""